In order to reduce the diameter of a multi-core cable such as an ultrasonic probe cable and reduce a manufacturing cost, a configuration in which a coaxial cable is not used as a signal line for transmitting a signal is known. In Patent Literature 1, a multi-core cable including five insulated conductors and one non-insulated conductor is described. In the multi-core cable described in Patent Literature 1, five insulated conductors and one non-insulated conductor are arranged in rows on the outer circumference of a tension member and are wound helically. In the multi-core cable described in Patent Literature 1, since the insulated conductors and the non-insulated conductor are arranged in rows and wound helically, favorable flexibility can be obtained. In addition, since the multi-core cable described in Patent Literature 1 does not include a coaxial cable, it is possible to reduce the diameter and a manufacturing cost.
However, in the multi-core cable described in Patent Literature 1, when insulated conductors are adjacent to each other with no non-insulated conductor interposed therebetween, two of five insulated conductors are adjacent to the non-insulated conductor and three of the insulated conductors are not adjacent to the non-insulated conductor and the insulated conductors are adjacent to each other. Since these adjacent insulated conductors are arranged in parallel in a longitudinal direction of the insulated conductors as signal lines and a state in which capacitive coupling between signal lines does not change is continuous, crosstalk increases. As described above, since the insulated conductors are arranged in parallel with equal intervals therebetween, there are problems in that crosstalk increases, signal strength decreases and signal quality deteriorates.